Notably, one SARS-CoV-specific antibody, CR3022, was found to bind potently with 2019-nCoV RBD as determined by ELISA and BLI (Figure 1(e,f)). It followed a fast-on (kon of 1.84 × 105 Ms−1) and slow-off (koff of 1.16 × 10−3 s−1) binding kinetics, resulting in a KD of 6.3 nM (Figure 1(f)). This antibody was isolated from blood of a convalescent SARS patient and did not compete with the antibody CR3014 for binding to recombinant S protein [5]. To further elucidate the binding epitopes of CR3022, we measured the competition of CR3022 and human ACE2 for the binding to 2019-nCoV RBD. The streptavidin biosensors labelled with biotinylated 2019-nCoV RBD were saturated with human ACE2 in solution, followed by the addition of the test antibodies in the presence of ACE2. As shown in Figure 1(g), the antibody CR3022 did not show any competition with ACE2 for the binding to 2019-nCoV RBD. These results suggest that CR3022, distinct from the other two SARS-CoV antibodies, recognizes an epitope that does not overlap with the ACE2 binding site of 2019-nCoV RBD.